Safe Boating

Think before trampling eelgrass

By Roz Butziger
Posted 4/21/16

You guide your boat into a new harbor, drop the anchor and look around. After a leisurely lunch, you decide to dinghy in to explore. Great idea, but a little caution can prevent damage to an …

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Safe Boating

Think before trampling eelgrass

Posted

You guide your boat into a new harbor, drop the anchor and look around. After a leisurely lunch, you decide to dinghy in to explore. Great idea, but a little caution can prevent damage to an important resource.

As the shore nears, you see long grass gracefully swaying back and forth underwater beside you. This is eelgrass, a plant inhabiting the shore from America to South Africa and Europe to Australia. Eelgrass, called Zostera, has blades about 1/4 inch wide, two to three feet long, and grows from three to 12 feet underwater. It is a submerged aquatic plant whose roots anchor it in the sandy or muddy bottom doing the important job of keeping the land from eroding away. It also buffers the wave action. Besides preserving our coastline, eelgrass provides food for ducks and geese and a habitat for eels. Within the bed of eelgrass are seeds, shellfish spat, larvae and eggs, making it a nursery for our bay. This important resource has suffered from trampling, dragging chains from moorings, and the action of propellers, so do be careful as you come ashore.

In addition, a wasting disease caused by a slime mold, destroyed many of the eelgrass beds decades ago. They are only now starting to recover slowly. In order to grow, of course, they require sunlight. When too much fertilizer is used in nearby gardens or lawns, it runs off into the bay and can cause excessive algae growth. The algae forms a mat on the surface, blocking the sunlight below. Herbicides, which wash into the cove, also can kill eelgrass. The loss of eelgrass was a major cause of the loss of scallops from Rhode Island. Without the eelgrass nursery, the young couldn’t develop. Loss of sea grasses is a worldwide problem discussed last year at the Seagrass Symposium in Sardinia, Italy. Scientists from tropical countries are very concerned also, since it is the primary food for the manatee and sea turtle. Even when eelgrass shoots are broken loose they form a detritus mat that becomes part of the food chain.

In the past, eelgrass has been used as food for livestock and in some areas of the world, for house insulation and roof thatching material. It was even used to stuff archery targets and mattresses. Now, we value it as an integral part of our bay’s ecosystem. NOAA, Save the Bay, DEM and others are working to repopulate areas where eelgrass has been destroyed. SCUBA divers are hand-transplanting thousands of plants, and hundreds of other volunteers participate in the transplanting also. URI is heading up projects growing eelgrass from seed. Transplant areas range from Wickford Harbor to Tiverton with the best results in Prudence Island, Coggeshall Point and Hog Island in Portsmouth. Success is being measured by an aerial mapping project. Also, the East Greenwich Sewer Plant has been upgraded, and this should improve the water quality that will affect eelgrass growth.

So, take care not to trample through the eelgrass or damage it with your propellers. Come ashore carefully and be a responsible guest of our bay.

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